Optoelectronic semiconductor components are used, for example, in an area of display technology where a homogeneously illuminated and high-contrast image is important.
A production method for conventional optoelectronic semiconductor components of the type mentioned involves firstly injection-molding a suitable plastic material around a prefabricated leadframe, the material forming a basic body for the housing of the device. The basic body has a cutout at the top side, connections of the leadframe being led into the cutout from two opposite sides. On one connection, the semiconductor chip, for example, an LED chip or a laser diode, is adhesively bonded and electrically contact-connected. A generally radiation-transmissive potting compound is then filled into the cutout and embeds the semiconductor body. This basic form of a surface-mountable optoelectronic semiconductor component is known, for example, from the article “SIEMENS SMT-TOPLED für die Oberflächenmontage”, [“SIEMENS SMT-TOPLED for surface mounting”], F. Möllmer und G. Waitl, Siemens Components 29 (1991), Issue 4, pages 147-149.
In order to generate, in a video display, for example, an image that is illuminated as homogeneously as possible and has the highest possible contrast, the light sources used are optoelectronic semiconductor components whose basic bodies are entirely diffusely reflective, that is to say they appear white, or basic bodies whose edge region is printed dark, and the rest of the basic body remains white. A dark embodiment of the basic body of the semiconductor components results in the generation of a high-contrast image. The contrast can be reduced by incidence of extraneous light, since the extraneous light is reflected at the emission area of the semiconductor component and the chip surface. By way of example, the contrast decreases as the brightness of the ambient light increases and the displayed image appears bleached out.
If the potting compound of the semiconductor components also contains scattering particles, then the emission area is diffusely reflective. The contrast and the homogeneity of the image can be optimized further by the use of screen devices and/or diffuser plates disposed upstream of the optoelectronic semiconductor components. However, these devices also lead to a loss of light, such that the light emitted by the semiconductor chip must have a higher brightness.